| Year | Count |
|---|---|
| 1972 | 5 |
| 1982 | 6 |
| 1991 | 5 |
| 1992 | 10 |
| 1993 | 23 |
| 1995 | 21 |
| 1996 | 56 |
| 1997 | 36 |
| 1998 | 47 |
| 1999 | 42 |
| 2000 | 53 |
| 2001 | 103 |
| 2002 | 65 |
| 2003 | 70 |
| 2004 | 146 |
| 2005 | 127 |
| 2006 | 176 |
| 2007 | 215 |
| 2008 | 113 |
| 2009 | 45 |
| 2010 | 66 |
| 2011 | 52 |
| 2012 | 5 |
| 2013 | 42 |
| 2014 | 30 |
| 2015 | 21 |
| 2016 | 16 |
| 2017 | 17 |
| 2018 | 16 |
| 2019 | 10 |
| 2021 | 10 |
| 2022 | 8 |
| 2023 | 10 |